This invention relates to endoscopic instruments of the class which includes a shaft whose distal end is inserted into a body cavity. At its distal end the instrument includes any one of a wide variety of active elements. At its proximal end there is a handpiece for actuation of the active element by the surgeon.
This type of instrument is well-known and is in widespread usage. The events at the site where the active elements accomplish their function are observed through a separate telescope system. Manipulation of the handpiece places the active element in an appropriate location and orientation and then actuates it to perform some surgical function. Such functions as occlusion, stapling, cutting and scission are commonplace.
Electro-surgical procedures are also enabled by such instruments. Cauterization is one such procedure, which frequently is used to staunch blood flow after a cutting procedure. Usually this electro-surgical sequence is done simultaneously with a cutting procedure. For example, scissor implements often form part of an electrical circuit that provides energy to coagulate and close a wound during the cutting phase.
A substantial industry has developed from these objectives. One example of a useful instrument is shown in applicant's U.S. Pat. No. 5,176,699, issued Jan. 5, 1993. This patent is representative of a large number of patents, all of which disclose and claim devices useful in endoscopy. It does not show the use of an instrument which is useful for electro-surgical procedures and which also is useful for procedures which do not use electrosurgery nor one which is especially suitable for one-time usage or for ready accommodation to a plurality of purposes.
Characteristic of these prior efforts is to provide at the active site a high frequency electrical current. This current is delivered at a high voltage through a long conductive member that extends through the instrument so as to be effective at the site, and not elsewhere. The problem is to get the electrical current to the exact place, and thereafter to diffuse it or otherwise conduct it to a ground such as the operating table without damage to other tissue, to the surgeon, or to the patient.
If all goes well, all of the current first goes only to the operation site, and from there it is harmlessly diffused.
The problem is that getting it only to the site is not a trifling matter. The extended metallic conductor from the handpiece to the active element is covered by insulation. Without the insulation, when this insulation would be the only protection, the patient or surgeon could be burned.
For insulation, these conductors are commonly coated with a layer of insulation that extends from the handset to the active element. This is a suitable arrangement if all goes well. However, the history of this instrumentation is replete with failures. Small “holidays” in the insulation caused by impact or by imperfect manufacture can and do permit substantial current leakage at weak or faulty places. Rubbing of the instrument against a rigid cannula through which it is passed and manipulated can also damage conventional insolation. The consequence, especially at the high frequencies employed, are internal burns in the patient, often to his serious damage.
Accordingly there exists a significant exposure to a risk that is avoidable only by perfection in the insulation. Perfection can be achieved, but in the practical world, one relies on statistical quality control and this leaves open the chance for failure in manufacture and in usage, although at a low rate. Still, a patient with a burn is not comforted by a low degree of risk.
It is an object of this invention to provide instrumentation that greatly reduces this kind of damage and risk.
Another disadvantage of known instrumentation of this type, not necessarily applicable only to electrosurgery, is the widespread use of the surgeon's thumb as the driver of the handpiece to actuate the active element. This is fatiguing and can lead to carpal tunnel problems for the surgeon. This invention eliminates this problem
Even further, conventional instrumentation does not provide for the quick and economically-justifiable substitution of one shaft and active element for another to an individual handpiece during a procedure. If such were made available to him, it would be a significant advantage to the surgeon and a major economic advantage, especially when provided as disposable one-time-use active elements. In contrast many instruments with disposable active elements include them as a unit with the handpiece, all of which is discarded after use.
The instrument of this invention enables the use of only one handpiece (which can readily be sterilized), and the ready removal and replacement of the shaft with another shaft each with a different active element during a procedure requiring only a momentary interruption and involving least distraction to the surgeon who does not have to remove his hand from the handpiece. As a consequence, there results a system in which a single handpiece can accommodate a sequence of single-use shafts and active elements, which themselves are reasonably affordable, and which improve the surgeon's access to different active elements during a procedure.
An expensive handpiece to be reused needs sterilization before each succeeding procedure, and this can often be economically justified. Alternatively, when a single use (single procedure) handpiece (usually plastic) is used and is to be discarded, still only one handpiece need be provided for the entire operation, and it can economically be discarded. With this invention, either way the instrument enables important savings.
This invention provides a surgical instrument system useful with or without electrosurgery provisions, and has an ergodynamically suitable handpiece that readily accommodates removable and replaceable shafts carrying respective active elements of various kinds. The variety of available active elements enables this system to function for nearly all endoscopic procedures.
Additionally, this invention enables the use of electrical conduitry that, while it may be coated with insulation, has the further advantage of being further isolated in insulation material of which the shaft is made.